Isengard

Isengard is under the command of the treacherous Istari Saruman, who in his vying for power threw his lot in with Sauron, the Dark Lord, in destroying the free folk of the West and claiming power over all. Under his command are the fighting Uruk-hai and a great arsenal of siege weapons, some the likes of which Middle-earth has never seen before.

Systems
Isengard uses a system called Industry expansion to unlock various heroes and units.

As the player expands infantry by building Excavations, Furnaces, Lumber Mills and Armouries they gain access to new units and heroes.